Interesting you should ask about how common "eighty-sixed" is... I was realizing as I read Katy's message (the first time) that, while I knew what she was saying, it had been a long time since I'd heard the expression. So I don't think it's all that common these days, but still most people here would know the meaning if someone used it in a sentence.

I think there's also a mental connection between "eighty-sixed" and "deep-sixed".